I want to add the total in an A/D conversion in adresh and adresl files and then split them into hundreds tens units, i know how to do the a/d routine, just need help with adding the two files using the conversion, maximum would be 500, anybody got any ideas how to do it in ASM using a pic16f690.

Sure. You can do division by repeated subtraction. You start by subtracting 100 from the A/D result until the result goes negative. Each time the result is positive you increment a counter. When the result goes negative you add 100 back and that is the reminder.

Now you switch to 10. Repeatedly subtract 10 until the dividend goes negative. Increment the 10's counter each time the result is positive. When the result goes negative add the 10 back in and the result will be the remainder.

All 8 bit processors have a carry flag that is used in multi-byte arithmetic. When the carry is 0, then the add with carry instruction is just like a normal add. When it is a 1, then the add with carry adds two bytes plus the carry bit in a single operation. You can extend this concept to operands with any number of bytes.